Engine fuel compositions

ABSTRACT

Novel soybean/terpene based fuel compositions and fuel additives are disclosed and claimed herein.

This is application claims the benefit of the filing of co-pending U.S. provisional application Ser. No. 60/920,200 filed Mar. 27, 2007, which is incorporated by reference herein in its entirety.

BACKGROUND AND SUMMARY OF THE INVENTION

Alternative fuels, as defined by the Energy Policy Act of 1992 (EPA Act), include ethanol, natural gas, propane, hydrogen, biodiesel, electricity, methanol, and p-series fuels. These fuels are being used worldwide in a variety of vehicle applications as a replacement, either in whole or in part, to petroleum based fuels (i.e. gasoline and diesel). Environmental advantages to using alternative fuels in vehicles include the reduction in harmful pollutants and exhaust emissions. In addition, most of these fuels can be domestically produced, thereby reducing the U.S.'s demand on foreign oil, as well as derived from renewable sources, as opposed to petroleum fuels.

There are various state and federal regulations currently in force with respect to the use of alternative fuels. As of Jan. 1, 2004, the state of California requires that all gasoline sold within that state to contain 5.7% ethanol. Eventually the blend in California will be increased to 85% ethanol/15% gasoline. One major problem with these ethanol/petroleum fuel blends is that they contain low BTU's, and therefore a reduction in fuel economy. It is therefore desirable to have an alterative fuel that affords all of the environmental advantages of conventional alternative fuels, without compromising fuel economy or power.

The present invention is directed to novel alternative fuels and fuel additives that replace the ethanol/petroleum fuel blends or be used in combination with such current ethanol/petroleum fuel blends. In particular, the inventive fuels and fuel additives comprise the soybean oil, in particular esterified soy bean oil, and one or more terpenes, such as limonene.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The present invention is directed to fuels and fuel additives for igniting engines, including internal combustion engines such as 2-cycle, 4-cycle, and diesel engines as well as jet propulsion engines. [As with any other fuel, the invention comprises adding the inventive fuel to the engine and igniting the engine] The term “inventive fuels” as used herein refers to those fuel compositions which may be used alone as alternatives to conventional fuels or as fuel additives to be used in combination with conventional fuels to ignite an engine. As use herein, “conventional fuels” shall mean petroleum-based fuels (including diesel fuel), nitromethane-based, and alternative-based fuels, such as alcohol-based fuels, for example.

All of the inventive fuels comprise a terpene as one of the components. Terpenes are widely distributed in nature and are present in nearly all living plants. It is generally recognized that the term “terpene” not only applies to isoprene oligomers, but also to their saturated or partially saturated isomers as well as to their derivatives, which are referred to as terpenoids, such as, for example, alcohols, aldehydes, esters, and the like. Terpenes have been widely used as flavor and perfume materials. Common monoterpenes include turpentine and limonene.

The preferred terpene is limonene which is a naturally occurring chemical found in high concentrations in citrus fruits and spices. [For ease of explanation, the present inventive fuel compositions (and fuel additive formulations) will be discussed herein with reference to limonene as the terpene fuel component. However, it is recognized that other suitable terpenes may be used, as well.] While d-limonene is the more preferred isomer, 1-limonene may also be used in the present invention (1-limonene is also found in naturally occurring substances such as pine-needle oil, oil of fir, spearmint, and peppermint, for example.) In addition to uses as flavor additives and perfume materials, limonene has been used in household and industrial cleaning products. Limonene is commercially available from Florida Chemical Company, Inc., for example, in three different grades, namely untreated/technical grade, food grade, and lemon-lime grade. The food grade comprises about 97% d-limonene, the untreated/technical grade about 95% d-limonene, and the lemon-lime grade about 70% d-limonene, the balance in all being other terpene hydrocarbons and oxygenated compounds. The technical and food grades of limonene are the most preferred for use in this invention and require no additional purification to remove impurities or water. The Applicant's U.S. Pat. Nos. 5,501,713, RE 37,629 (reissue of U.S. Pat. No. 5,575,822), and U.S. Pat. No. 5,607,486, all of which are incorporated by reference herein in their entireties, describe the use of limonene in engine fuels and fuel additives.

In addition to one or more terpenes, the inventive fuels include a soybean oil product. While unprocessed soybean oil may be employed, the preferred soybean oil product is an esterified soybean oil, most preferably the methyl ester of soybean oil. As you used herein, the “soybean oil” shall include crude or pure unprocessed soybean oil, all esterified products of soybean oil, such as the methyl ester of soybean oil, and any other suitable derivatives of soy bean oil.

The inventive fuel may also include a compound for increasing the flashpoint, and therefore BTU's. A preferred compound is an aliphatic hydrocarbon solvent, more preferably an aliphatic petroleum distillate compound, as described in the inventor's U.S. Pat. No. RE 37,629, described above. The most preferred aliphatic petroleum distillate is VM&P Naphtha, which has a flash point of about 50° F., emits relatively few volatile organic compounds (VOC) when burned, blends well with limonene and the other components of the fuel, and is relatively inexpensive. Other aliphatic hydrocarbon solvents may also be used, preferably those having flash points ranging from about 45° F. to about 75° F. in order to ignite the engine. The concentration of aliphatic petroleum distillates may range from about 1 w/w % to about 90 w/w %, with the more preferred ranges depending upon the type of engine used, as discussed further below.

The inventive fuels may also include a small amount of butylated hydroxytoluene (BHT), which is an effective as an antioxidant to decrease the auto-oxidation of limonene or other terpenes in the fuel which undergo auto-oxidation. Preferably, about 0.002 grams of BHT per gallon of fuel is added. Other suitable anti-oxidants include butylated hydroxyanisole (BHA) and other standard anti-oxidants, now known or later developed, by those of ordinary skill in the art for preventing oxidation of terpenes. Exemplary anti-oxidants include, but are not limited to, 2,2′-methylene-bis(4-ethyl-6-tert-butylphenol), 2,2′-methylene-bis-(4-methyl-6-tert-butylphenol), 4,4′-butylidene-bis(5-methyl-6-tert-butylphenol), 4,4′-methylene-bis(2-methyl-6-tert-butylphenol), 4,4′-thio-bis(3-methyl-6-tert-butylphenol), 4,4′-methylene-bis(2,6-di-tert-butylphenol), stearyl-β(3,5-di-tert-butyl-4-hydroxyphenol)-propionate, 1,3,5-trimethyl-2,4-6-tris(3,5-di-tert-butyl-4-hydroxybenzylbenzene), 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butyl)-butane, tetrakis[methylene(3,5-di-tert-butyl-4-hydroxycinnimate)]methane, dilauryl thiodipropionate, distearyl thiodipropionate, UV absorbers derived from benzophenone, triazole, and salicylate compounds, and combinations thereof. U.S. Pat. No. 6,858,217 also discloses anti-oxidants for terpene compounds.

Preferred engine fuel compositions of the present invention are listed below:

(A) soybean oil, limonene, and petroleum gasoline having any variety octane numbers (i.e. 85, 87, 92) or diesel fuel.

(B) soybean oil, limonene, a naptha product (e.g. VM&P Naphtha) and/or BHT, and petroleum gasoline or diesel fuel.

(C) soybean oil, limonene, ethanol or ethanol/petroleum gasoline blends comprising 5% to 85% ethanol.

(D) soybean oil, limonene, ethanol or ethanol/petroleum gasoline blends (comprising 5% to 85% ethanol), a naphtha product (e.g. VM&P Naphtha) and/or BHT.

The inventive fuels may also in included a combination of soybean oil, limonene (or other terpenes), and jet propulsion fuels, which is similar to conventional petroleum fuels, but further contains kerosene.

Preferred engine fuel compositions include from about 0.5%v/v to about 10% d-limonene, from about 2% v/v to about 15% esterified soybean oil (preferably methyl ester of soybean), and from about 80% v/v to about 94% v/v petroleum-based gasoline or diesel fuel.

Additional engine fuel compositions include from about 0.5%v/v to about 10% v/v d-limonene, from about 2% v/v to about 15% v/v esterified soybean oil (preferably methyl ester of soybean), from 5% v/v to about 85% v/v ethanol, and from about 10% v/v to about 95% v/v petroleum gasoline or diesel fuel.

To the foregoing fuel blends, from about 1% v/v to about 15% of a naphtha compound (e.g. VM&P Naphtha). Similarly, about 500 ppm of a suitable anti-oxidant (e.g. BHA, BHT, and the like) may be added to the terpene component of the fuel.

An exemplary formulation comprises 90% v/v conventional petroleum gasoline, 5.7% v/v ethanol, and 4.3% soybean/d-limonene composition, the soybean/d-limonene compositions comprising 90% methyl ester of soybean oil and 10% d-limonene.

In formulating the various fuel blends, the inventor used a product called CITRUSOY SUPER HIGH FLASH (vended by Florida Chemical Col, Winter Haven, Fla.). This product includes 90% w/w methyl ester of soybean oil and 10% w/w d-limonene. The inventor also used CITRUSOY HIGH FLASH (Florida Chemical Co.), which includes 50%v/v methyl ester of soybean oil and 50% w/w d-limonene.

No special equipment is required to formulate the inventive fuel compositions, and all mixing may be performed under ambient conditions. However, depending upon which components are used in a particular fuel formulation, the order of mixing may be important. In all cases, it is preferable to add slowly the various components to the terpene. If an aliphatic petroleum distillate, in particular VM&P Naphtha, are to be added, the methanol is added, with stirring, followed by VM&P Naphtha, or vice versa.

EXAMPLE 1

The follow fuel composition (i.e. Fuel Composition A) was tested against a standard fuel in a 4-cycle Briggs & Stratton engine: 90% v/v petroleum gasoline (91 octane, unleaded), 5.7% v/v ethanol, and 4.3% soybean/d-limonene composition (the soybean/d-limonene comprised 90% methyl ester of soybean oil and 10% d-limonene). The standard fuel was 91 octane unleaded gasoline.

One liter of the standard fuel was added to the 4-cycle engine, and the engine was allowed to run for one hour (RPM=Idle). The following results were recorded:

Head temperature: 166° F.

Response time rating: 6-7 (subjective, based on a scale of 1-10, with 10 being best)

Exhaust temperature: 365° F.

After the foregoing results were recorded for the standard, one liter of Fuel Composition A was added to the same 4-cycle engine, and the engine was again allowed to run for one hour. The following results were recorded:

Head temperature: 154° F.

Response time: 9-10 rating (subjective, based on a scale of 1-10, with 10 being best)

Exhaust temperature: 329° F.

The results of the testing revealed that the inventive fuel composition ran more efficiently than the conventional gasoline standard with a 26% increase in efficiency. 

1. An engine fuel composition comprising a soybean oil compound, a terpene, and conventional petroleum based or diesel fuel.
 2. The engine fuel composition of claim 1, further including ethanol.
 3. The engine fuel composition of claim 1, wherein said terpene is limonene and said soybean oil compound is an esterified soybean oil.
 4. The engine fuel composition of claim 3, wherein said esterified soybean oil compound is the methyl ester of soybean oil.
 5. The engine fuel composition of claim 3, further including a naphtha product.
 6. The engine fuel composition of claim 3, wherein said composition comprises from about 0.5% v/v to about 10% v/v of said limonene, from about 2% v/v to about 15% v/v of said soybean oil, and from about 80% to about 94% of said petroleum based or diesel fuel.
 7. The engine fuel composition of claim 6, further including from about 1% v/v to about 15% v/v of a naphtha compound.
 8. The engine fuel composition of claim 6, further including an anti-oxidant.
 9. The engine fuel composition of claim 2, where said composition comprises from about 0.5% v/v to about 10% v/v limonene, from about 2% v/v to about 15% v/v of said soybean oil, from about 5% v/v to about 85% of said ethanol, and from about 10% v/v to about 95% v/v petroleum based or diesel fuel.
 10. The engine fuel composition of claim 9, further including from about 1% v/v to about 15% v/v of a naphtha compound.
 11. A method for igniting an engine, said method comprising (a) adding the fuel composition of claim 1 to an engine and (b) igniting said engine.
 12. The engine fuel composition of claim 11, further including ethanol.
 13. The engine fuel composition of claim 11, wherein said terpene is limonene and said soybean oil compound is an esterified soybean oil.
 14. The engine fuel composition of claim 13, wherein said esterified soybean oil compound is the methyl ester of soybean oil.
 15. The engine fuel composition of claim 13, further including a naphtha product.
 16. The engine fuel composition of claim 13, wherein said composition comprises from about 0.5% v/v to about 10% v/v of said limonene, from about 2% v/v to about 15% v/v of said soybean oil, and from about 80% to about 94% of said petroleum based or diesel fuel.
 17. The engine fuel composition of claim 16, further including from about 1% v/v to about 15% v/v of a naphtha compound.
 18. The engine fuel composition of claim 16, further including an anti-oxidant.
 19. The engine fuel composition of claim 12, where said composition comprises from about 0.5% v/v to about 10% v/v limonene, from about 2% v/v to about 15% v/v of said soybean oil, from about 5% v/v to about 85% of said ethanol, and from about 10% v/v to about 95% v/v petroleum based or diesel fuel.
 20. The engine fuel composition of claim 19, further including from about 1% v/v to about 15% v/v of a naphtha compound. 